Change of State
Physics ⇒ Heat and Thermodynamics
Change of State starts at 8 and continues till grade 12.
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See sample questions for grade 12
A sample of water is heated from 20°C to 100°C and then converted to steam at 100°C. List the energy changes involved in this process.
Describe the difference between evaporation and boiling.
Describe what happens at the molecular level during condensation.
During the melting of ice, the temperature of the system does not change even though heat is being supplied. Explain why.
Explain why ice floats on water.
A 250 g block of ice at 0°C is placed in 500 g of water at 30°C. Calculate the final temperature of the mixture. (Assume no heat loss, specific heat of water = 4.18 kJ/kg·K, latent heat of fusion = 334 kJ/kg)
A scientist observes that dry ice (solid CO₂) disappears at room temperature without forming a liquid. What process is occurring?
A sealed container holds 2 kg of water at 100℃ and 1 atm pressure. If the pressure inside the container is suddenly increased to 2 atm, what will happen to the boiling point of water? Explain your answer.
Which of the following best describes the process of sublimation?
(1) Solid to liquid
(2) Liquid to gas
(3) Solid to gas
(4) Gas to solid
Which of the following best explains why pressure cookers cook food faster?
(1) They increase the boiling point of water
(2) They decrease the boiling point of water
(3) They increase the latent heat of vaporization
(4) They decrease the latent heat of vaporization
Which of the following factors does NOT affect the rate of evaporation?
(1) Surface area
(2) Humidity
(3) Atmospheric pressure
(4) Color of the liquid
Which of the following is an example of deposition?
(1) Frost forming on a cold window
(2) Ice melting
(3) Water boiling
(4) Alcohol evaporating
The _______ heat of a substance is the amount of heat required to change the state of 1 kg of the substance without changing its temperature.
The amount of heat required to change 1 kg of a solid into liquid at its melting point is called _______.
The energy required to change the state of a substance without changing its temperature is called _______.
The process of changing a gas directly into a solid is called _______.
Is it possible for water to boil at temperatures below 100°C?
True or False: Freezing is an exothermic process.
True or False: The latent heat of vaporization is always greater than the latent heat of fusion for the same substance.
True or False: The melting point and freezing point of a pure substance are the same temperature.
